Abstract
We describe the fabrication of organically modified sol-gel (ORMOSIL) planar optodes for mapping the two-dimensional oxygen distribution in sediments. All sensor foils were based on the use of ruthenium(II)-tris-(4,7-diphenyl-1,10-phenantrolin)perchlorate, which is a fluorescent dye quenched dynamically by oxygen. Sensors made with different sol-gel immobilisation matrices, different concentrations of precursors and indicator dye, as well as different types of scattering particles co-immobilised in the sensor foil were investigated systematically. Optimal sensor performance was obtained with dye concentrations of 2-10 mmol/kg in an immobilisation matrix made of diphenyldiethoxy-silan and phenyltriethoxy-silan precursors with addition of organically coated TiO2 particles. The sensors exhibited a good mechanical stability and a high sensitivity from 0% to 100% oxygen, which remained constant over at least 36 days. The planar optodes were used with a fluorescent lifetime imaging system for direct mapping of the spatio-temporal variation in oxygen distribution within marine sediment inhabited by the polychaete Hediste diversicolor. The measurements demonstrated the spatio-temporal heterogeneity of the oxygen distribution in bioturbated sediments due to burrow structures and non-constant irrigation activity of the polychaete, which is difficult to resolve with microsensors or with traditional biogeochemical techniques. (c) 2005 Elsevier B.V All rights reserved.
Original language | English |
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Pages (from-to) | 262-276 |
Number of pages | 15 |
Journal | MAR CHEM |
Volume | 97 |
Issue number | 3-4 |
DOIs | |
Publication status | Published - 2005 |
Keywords
- O-2
- Chemistry, Multidisciplinary
- SEA
- LIFETIME IMAGING-SYSTEM
- COATINGS
- Oceanography
- MARINE-SEDIMENTS
- MICRO-OPTODES
- FLUORESCENCE
- BIOLOGICAL SAMPLES
- LUMINESCENCE QUENCHING BEHAVIOR
- RU(II) COMPLEX